Method of unloading bulk materials from vessels and device for implementing same

ABSTRACT

The method of unloading bulk materials from vessels resides in a mechanical loosening of the bulk material in the intake zone by virtue of vibration with a simultaneous supply of the aerating air in the direction of the inlet opening of a taking device, the aerating air being supplied pulsewise so that the frequency of pulses is synchronized with the material vibration frequency, taking the loosened and aerated bulk material through suction, and conveying the material by the air. A device carrying this method into effect comprises a sucking nozzle connected to the material conveying device, a loosening device made fast on the sucking nozzle, and an aerator attached to the loosening device. The loosening device is made as the frustum of a cone with its smaller base facing downwards and embracing the sucking nozzle, the lateral surface of the cone being formed by a number of spaced-apart separate ribs, whereas the inlet opening of the sucking nozzle is located below the loosening device. The aerator is located under the nozzle and is made as an annular tube with outlet holes facing the nozzle. Installed on the loosening device is a pneumatic vibrator whose inlet branch pipe is connected to a pressure line, while its outlet branch pipe is connected to the inlet opening of the aerator.

FIELD OF THE INVENTION

The present invention relates to pneumatic transport means and moreparticularly to methods of unloading bulk materials from vessels and todevices implementing this method.

The invention can most advantageously be used for unloading bulkmaterials from ships. The invention can also be used for unloading bulkmaterials from railway hopper cars.

BACKGROUND OF THE INVENTION

It is known that in any method of bulk material transportation andstorage it is liable to get consolidated. This hinders its effectiveintake by any pneumatic transport methods during unloading. Therefore,when unloading a bulk material it is, as a rule, loosened and aerated tobring it in a fluidized state which is optimum for the pneumatictransportation.

For bulk material transportation a method is known to consist in thatthe mechanically pre-loosened material is aerated by an additionalquantity of air supplied directly into the nozzle mouth.

A disadvantage of this method stems from the fact that the materialtransportation is intensified only in the accelerating portion of thenozzle. This can be effective only in combination with a mechanism, forexample a worm feeder, used to supply the material from the suction zoneto the zone of supply of the additional amount of aerating air, i.e., tothe nozzle mouth. This complicates the construction of the pneumatictransport equipment and increases the cost of transportation.

A pneumatic transport installation for re-loading bulk materials fromships is known to comprise a sucking nozzle with a loosening meansprovided with an electric drive and a device for supplying air to themouth of the sucking nozzle. This installation suffers from the samedisadvantages as the above-mentioned method. In addition, theinstallation fails to provide an adequately efficient intake of materialbecause the loosening performed mechanically by two rotable blades failsto secure a symmetrical feed of the material to the intake zone.

In another known method of unloading bulk materials from vessels, thematerial being unloaded is mechanically loosened and forced-aerated inthe intake zone, i.e., under the taking means, the aerating air beingsupplied continuously in nondirectional flows. The mixture of the bulkmaterial with air produced in the intake zone is sucked by the takingmeans, where a reduced pressure is maintained, and is transported byvirtue of the air.

The device carrying this method into effect comprises a sucking nozzlecommunicated with a suction pump through a pipe line used as a means fortransporting the material. The end of the sucking nozzle facing thematerial being unloaded has a bevelled edge, i.e., the plane of theinlet opening of the nozzle is at a certain angle to the horizontalplane so that the inlet opening of the nozzle is elliptical. A verticalhollow shaft driven by an electric motor and coupled with a pressureline is attached to the sucking nozzle on the size of the bevelled edge.The lower end of the shaft has a hollow disc rigidly installed thereon,which extends almost to the center of the inlet opening of the suckingnozzle. The disc is made of a porous cermet material. The lowerextension of the hollow shaft protrudes into the disc so that the shaftinterior and the disc interior are intercommunicated. The disc performsthe function of both the loosening means and the aerator for the bulkmaterial being unloaded.

The hollow shaft with the disc is rotated by a motor, and the discloosens the material in the intake zone under the nozzle. In addition,air is supplied from the pressure line through the hollow shaft, saidair emerging through the porous walls of the disc to aerate thematerial, thus producing a mixture of the material with the air. Thematerial-and-air mixture is sucked by the nozzle and transported alongthe pipe line. The device has also a mechanism for moving the nozzlewhich provides the lowering of the nozzle as the material is unloaded,as well as the movement of the nozzle in other directions.

A disadvantage of the above method for unloading bulk materials and thedevice implementing this method consists in low efficiency of materialintake due to low aerodynamic efficiency of the nozzle having a bevellededge, as well as owing to non-uniform loosening and aeration of thematerial with respect to the longitudinal axis of the nozzle in theintake zone. This is accounted for by the fact that the porous discperforming the aeration and loosening covers only a portion of the inletopening of the nozzle and the material under that part of the nozzlewhich is far from the disc is aerated and loosened worse than in theimmediate vicinity of the disc. The non-symmetrical arrangement of thedisc with respect to the sucking nozzle leads also to aeration of thematerial not only in the intake zone, but also in other zones where theintake is not performed, i.e. to losses of the aerating air. Said lossesof the aerating air are also aggravated by the fact that the air issupplied through a porous disc in non-directional flows.

Moreover, the horizontal disc hampers the movement of the sucking nozzleinto the material, especially when the material being unloaded is in theconsolidated state.

The above disadvantages affect adversely the capacity of the materialunloading and enhance the energy consumption for the unloading. Finally,such a constructional arrangement of the unloading device fails toprovide its operational reliability and safety, especially when used ina bilge of the ship being unloaded, where there are metallic uprights,bulkheads, etc., since it has rotating elements, viz., the disc and theshaft, and current-conducting elements to supply voltage to the electricmotor.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a method ofunloading bulk materials from vessels and a device implementing thismethod, which ensure an increase in the unloading process capacity dueto an increase in the efficiency of intake of the material beingunloaded.

A further object of the invention is to reduce the amount of power forunloading bulk materials from vessels as a result of an economicalconsumption of the air used for aerating the material.

Another object of the invention is to increase the operationalreliability and safety of the device for unloading bulk materials fromvessels, as well as to simplify its construction.

With these and other objects in view, there is proposed a method forunloading bulk materials from vessels comprising a simultaneousmechanical loosening and forced aeration of the bulk material to beunloaded in the intake zone, taking the loosened and aerated materialthrough suction of the taking means due to a vacuum maintained in thetaking means, and transporting the material from the taking means byvirtue of the air, wherein, according to the invention, the loosening ofbulk material is performed by virtue of vibration, the aerating airbeing supplied towards the inlet opening of the taking means in pulseswhose frequency is synchronized with the material vibration frequency.

The method proposed provides an intensive intake of material due to anefficient fluidization of the material in the intake zone as a result ofthe combined action on the material of the vibration and the pulsedaerating air supply. The pulsed air supply facilitates an additionalloosening of the material since the energy developed by an individualpulsed air jet is higher than that of a continuous escape, and if theair supply pulses are synchronized with the vibration, then the forcesacting on the material as a result of these two effects are added. Theaerating air flows directed to the inlet opening of the taking meansprovide an economical air consumption.

It is desirable to vibrate the material and to supply the aerating airat a frequency within the range from 2 to 60 Hz. Said range is definedby the fact that, in case of vibration at frequency below 2 Hz, thematerial is loosened inadequately even when using highly friablematerial while the vibration at a frequency above 60 Hz results in itsgetting still more consolidated.

It is also desirable to ensure intersection of the aerating air flows atthe longitudinal axis of the taking means. This contributes to a bettermaterial supply to the taking means.

With these and other objects in view, there is also proposed a devicefor unloading bulk materials from vessels, comprising a sucking nozzleconnected with a material transportation means, a loosening meansattached to the sucking nozzle, and an aerator connected to a pressureline, wherein, according to the invention, the loosening means is ineffect the frustum of a cone with its smaller base facing downwards andembracing the sucking nozzle, the lateral surface of the cone beingformed by a number of space-apart separate ribs and the inlet opening ofthe sucking nozzle being located below the loosening means, while theaerator is made as an annular tube provided with outlet holes andattached to the loosening means under the nozzle, said holes facing thenozzle, and is connected to a pressure line via a pneumatic vibratorinstalled on the loosening means.

The loosening means installed around the nozzle and made as the frustumof a cone with a ribbed surface provides a symmetrical supply of theloosened material to the inlet opening of the nozzle, while the annularaerator located under the nozzle and the air supply holes of the aeratorfacing the inlet opening of the nozzle provide a uniform materialaeration in the intake zone, the entire aerating air being supplied tothe intake zone.

Moreover, the construction of the loosening means and the aerator of theinvention makes it easier to introduce the nozzle into the mass of thematerial being unloaded. The proposed device is simple and reliable inoperation because of the use of the pneumatic vibrator as a drive of theloosening means. In the device proposed an economical power consumptionis achieved also by using the spent air of the pneumatic vibrator as anaerating air.

In accordance with an embodiment of the invention the loosening means isfastened resiliently to the sucking nozzle in the tangential directionwith respect to the sucking nozzle.

Such a fastening of the loosening means to the nozzle eliminates anundesirable axial and radial vibration components.

It is also desirable to arrange the outlet holes of the aeratorequidistantly from each other and to orient these holes so that theiraxes cross at the longitudinal axis of the sucking nozzle. This providesa symmetrical aeration of the material with respect to the longitudinalaxis of the sucking nozzle.

The invention will now be explained in greater detail with reference toa specific embodiment thereof, taken in conjunction with theaccompanying drawings, wherein:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a general schematic view of the device for unloading bulkmaterials from vessels, according to the invention;

FIG. 2 is an enlarged-scale view of the sucking nozzle with theloosening means and the aerator of the device of FIG. 1 and

FIG. 3 is a top view of FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION

A method of unloading bulk materials from vessels, according to theinvention is implemented as follows.

The taking means in which/terminates the sucking line of the device forunloading bulk material, kept continuously under vacuum, is sunk, forexample, into the bilge of a ship filled with a bulk material. Thetaking means is brought in contact with the material and is immersedinto the bulk of the material, whereas the material in front of theinlet opening of the taking means, i.e., in the intake zone, is loosenedby vibration in the horizontal plane and by a simultaneous forcedaeration. The aerating air is supplied in pulses towards the inletopening of the taking means so that flows of the aerating air cross atthe longitudinal axis of the taking means. The frequency of air supplypulses is synchronized with the frequency of material vibration and isset within the range from 2 to 60 Hz depending upon the material to beunloaded, for example, 8 Hz for a dust-like cement.

The material vibration at a frequency below 2 Hz fails to provide anefficient loosening of the material, while the vibration at frequencyabove 60 Hz contributes to consolidation of material.

A stable zone of fluidized material, i.e., of the loosened materialsaturated with air, is formed within the intake zone as a result of acombined action of the vibration and the pulsed aerating air flows onthe material, which zone displaces as the taking means is displaced. Thematerial fluidization proceeds intensely because the material isdisplaced with respect to the aerating air jets in synchronism with thevibration frequency due to sluggishness of the bulk of material beinghandled. An area of material considerably exceeding the cross-sectionalarea of the jet is, therefore, exposed to each of the air jets.Moreover, this causes a destruction of the channels being washed out byair jets in the material body, and the consolidated material between thejets is loosened. This facilitates the aeration process as well. Thepulsed air supply contributes to the destruction of air channels, andthe loosening and aeration of the material consolidated between jetsproceeds more intensely, if the frequency of kicks experienced by thematerial due to the action of a next air pulse in the pulsed aeration issynchronized with the frequency of kicks caused by the vibration, inwhich case the forces of both are added.

The loosened and aerated material is sucked by the taking means in theintake zone and then are further transported by the air. The materialintake is facilitated by the fact that the portion of the material whichundergoes the direct action of the pulsed flow of aerating air displacesin the direction of the inlet opening of the taking means.

Referring now to FIG. 1, the device for unloading bulk materialcomprises a nozzle 1 connected through a flexible hose 2 to a materialtransportation means 3. Fastened on the sucking nozzle 1 is a looseningmeans 4 on which a pneumatic vibrator 5 is installed to ensuretangential direction of vibration of the pneumatic vibrator 5 and,hence, that of the loosening means 4 with respect to the nozzle 1. Anaerator means 6 is disposed under the sucking nozzle 1 and is fitted tothe loosening means 4.

The sucking nozzle 1 is supported by an electric telpher 7. However, anyother hoisting mechanism may be used to move the nozzle 1.

In the embodiment of the invention being disclosed the materialtransportation means 3 is a common type sucking pressure installationwhich is connected to a pressure line 8 provided with shut-off valves 9and 10. The pressure line 8 is used to feed the material transportationmeans 3 and to aerate a material 11 being unloaded. However, a suckinginstallation may be used as the transportation means 3, in this case thepressure line 8 being utilized only to aerate the material 11.

Referring to FIG. 2, the loosening means 4 is the frustum of a coneembracing the sucking nozzle 1 and installed with its smaller basefacing downwards. An inlet opening 12 of the nozzle 1 is below theloosening means 4. The lateral surface of the loosening means 4 consistsof spaced-apart separate ribs 13 (FIG. 3). The ribs 13 are joined to thehousing of the sucking nozzle 1 by pulling rods 14 (FIG. 2) which aremade stiff longitudinally and resilient laterally i.e., in thetangential direction with respect to the nozzle 1.

The aerator 6 is attached to the loosening means 4 through uprights 15and is formed by an annular tube arranged concentrically with the nozzle1 and provided with outlet holes 16 facing the nozzle 1 and spacedequidistantly. An inlet opening 17 of the aerator 6 is connected to anoutlet branch pipe 19 (FIG. 3) of the pneumatic vibrator 5 through aflexible air duct 18. An outlet branch pipe 20 of the pneumatic vibrator5 is connected to the pressure line 8 (FIG. 1) through a flexible airduct 21.

As it is shown in FIG. 2, the axes of the outlet holes 16 of the aerator6 cross at the longitudinal axis of the sucking nozzle 1.

Welded to the housing of the nozzle 1 are lugs 22 for slinging(suspension) of the nozzle 1 to move it by the electric telpher 7 (FIG.1).

The device proposed herein operates as follows. The materialtransportation means 3 is thrown into operation, and the valve 9 of thepressure line 8 is opened for compressed air to pass therethrough fromany source (not shown). The sucking nozzle 1 is moved by the electrictelpher 7 until it comes in contact with the material 11 to be unloadedand the inlet opening 12 (FIG. 2) is pressed against the material 11(FIG. 1). This allows vacuum in the nozzle 1 to be increased up to theworking value, as well as that in the hose 2. The aerator 6 embeds intothe material to be unloaded 11.

The shut-off valve 10 of the pressure line 8 is opened, and thecompressed air is fed through the air duct 21 to the pneumatic vibrator5 and activates it, thus causing the vibration of the pneumatic vibrator5 and, hence, that of the loosening means 4 with the ribs 13 (FIG. 2)and of the aerator 6 in the tangential direction with respect to thesucking nozzle 1. The material 11 to be unloaded (FIG. 1) in the intakezone which undergoes the simultaneous action of vibration in thehorizontal plane and a directed air jets escaping from the outlet holes16 (FIG. 2) of the aerator 6 is loosened and saturated uniformly withair. The aerated material is sucked by the nozzle 1 and is transportedthrough the flexible hose 2 (FIG. 1) to the transportation means 3 andfurther on to the place of unloading.

The surface of the carter formed by the ribs 13 (FIG. 3) of thevibrating loosening means 4 in the bulk of the material being unloaded11, when it is taken, crumbles continuously; the crumbled material getsinto the space between the inlet opening 12 (FIG. 2) of the nozzle 1 andthe aerator 6 where it undergoes the action described above and issucked by the nozzle 1, thus giving place to a new layer of the material11 (FIG. 1) crumbling from under the loosening means 4.

The invention proposed substantially increases the capacity of unloadingof bulk materials, without an increase in power consumption, reduces thetime required for unloading ships, as well as increases the safety andreliability in service since the unloading device has nocurrent-conducting and rotating components.

While a particular embodiment of the invention has been shown anddescribed, various modifications thereof will be apparent to thoseskilled in the art and therefore it is not intended that the inventionbe limited to the disclosed embodiment or to the details thereof and thedepartures may be made therefrom within the spirit and scope of theinvention as defined in the appended claims.

What is claimed is:
 1. A device of unloading a bulk material fromvessels, comprising:a sucking nozzle for taking said bulk material to betransported; a bulk material transportation means connected to saidsucking nozzle; a means for loosening said bulk material being attachedto said sucking nozzle and embracing said sucking nozzle so that aninlet opening of said sucking nozzle is disposed below said looseningmeans; said loosening means being made as the frustum of a coneinstalled with its smaller base facing downwards, while the lateralsurface of said cone is formed by a number of spaced-apart separateribs; a means for supplying aerating air into said bulk material, beingattached to said loosening means and installed under said suckingnozzle; said aerating air supply means being made as an annular tubehaving an inlet opening and provided with a plurality of outlet holesfacing said sucking nozzle; a pneumatic vibrator attached to saidloosening means and having an inlet branch pipe and an outlet branchpipe, said outlet branch pipe of said pneumatic vibrator being connectedto said inlet opening of said aerating air supply means; and a pressureline connected to said inlet branch pipe of said pneumatic vibrator. 2.A device for unloading bulk materials as defined in claim 1 whichcomprises further rods used to attach said loosening means to saidsucking nozzle;said rods being made resilient in the tangentialdirection with respect to said sucking nozzle.
 3. A device for unloadingbulk materials as defined in claim 2, wherein said outlet holes of saidaerating air supply means are spaced equidistantly from each other,while the axes of said holes cross at the longitudinal axis of saidsucking nozzle.
 4. A device for unloading bulk materials as defined inclaim 1, wherein said outlet holes of said aerating air supply means arespaced equidistantly from each other, while the axes of said holes crossat the longitudinal axis of said sucking nozzle.